Habitat selection of foraging chick-rearing European shags in contrasting marine environments
Impacts of anthropogenic activities on coastal seabirds might be extensive, especially in the breeding season. Identifying important foraging areas and associated habitats is important for a proper management of seabirds. To identify habitat characteristics driving the selection of foraging sites of breeding European shags Phalacrocorax aristotelis, this study used tracking data (GPS- and TDR-loggers), from 282 individual birds comprising 905 foraging trips and 27,303 dives with known locations, to create habitat selection models. To explore possible effects of regional differences in habitat on foraging behavior, the study was performed at two Norwegian colonies, Sklinna in the Norwegian Sea (65°N, 11°E) and Hornøya in the Barents Sea (70°N, 31°E), with distinct differences in seascape structure and habitat availability. Shags at Sklinna foraged further away from the colony than those at Hornøya but diving depth and duration were similar at the two colonies. In both colonies, sea depth was an important predictor of habitats selected by chick-rearing shags during foraging, with birds preferring shallow depths. At Sklinna, shags also selected for flat areas with high probability of kelp forest occurrence. There was no difference in trip length and duration between sexes, but males dived deeper than females in both colonies. This suggests that males and females might utilize different microhabitats within the same foraging area. The study discusses the application of habitat selection modeling to identify important foraging areas for coastal seabirds, and how this may contribute to the management, conservation and assessment of impacts of human activities.
We would like to thank all field assistants at Sklinna and Hornøya for invaluable help. We also thank R. Barrett for valuable comments on earlier drafts of the manuscript, and S.P. Luque for valuable help with the DiveMove analysis. The study was funded through SEAPOP (www.seapop.no), CEDREN (www.cedren.no), the Norwegian Environment Agency, the Norwegian Water Resources and Energy Directorate and the Norwegian Institute for Nature Research.
Compliance with ethical standards
Conflict of interest
The authors declare that there are no conflicts of interest.
All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted. The study was approved by the Norwegian Animal Research Authority (FOTS ID: 3238, 5148 and 8616). This article does not contain any studies with human participants performed by any of the authors.
- Bekkby T, Moy F, Olsen H, Rinde E, Bodvin T, Bøe R, Steen H, Grefsrud ES, Espeland SSH, Pedersen A, Jørgensen NM (2013) The Norwegian Programme for mapping of marine habitats – providing knowledge and maps for ICZMP. In: Moksness E, Dahl E, Støttrup J (ed) Global challenges in integrated coastal zone management, Wiley-Blackwell. ISBN 978-0-470-65756-0Google Scholar
- Birdlife International (2010) Marine Important Bird Areas toolkit: standardised techniques for identifying priority sites for conservation of seabirds at sea. Birdlife International, CambridgeGoogle Scholar
- Bogdanova MI, Wanless S, Harris MP, Lindström J, Butler A, Newell MA, Sato K, Watanuki Y, Daunt F (2014) Among-year and within-population variation in foraging distribution of European shags Phalacrocorax aristotelis over two decades: implications for marine spatial planning. Biol Conserv 170:292–299. doi: 10.1016/j.biocon.2013.12.025 CrossRefGoogle Scholar
- Boyd C, Castillo R, Hunt GL Jr, Punt AE, VanBlaricom GR, Weimerskirch H, Bertrand S (2015) Predictive modelling of habitat selection by marine predators with respect to the abundance and depth distribution of pelagic prey. J Anim Ecol 84:1575–1588. doi: 10.1111/1365-2656.12409 CrossRefGoogle Scholar
- Cramp S, Simmons KEL (1977) The birds of the Western Palearctic, vol I. Oxford University Press, OxfordGoogle Scholar
- Daunt F, Bogdanova M, McDonald C, Wanless S (2015) Determining important marine areas used by European shag breeding on the Isle of May that might merit consideration as additional SPAs (2012). JNCC Report No 556. JNCC, PeterboroughGoogle Scholar
- ESRI (2011) ArcGIS desktop: Release 10. Environmental Systems Research Institute, RedlandsGoogle Scholar
- Fauchald P, Anker-Nilssen T, Barrett RT, Bustnes JO, Bårdsen BJ, Christensen-Dalsgaard S, Descamps S, Engen S, Erikstad KE, Hanssen SA, Lorentsen S-H, Moe B, Reiertsen TK, Strøm H, Systad GH (2015) The status and trends of seabirds breeding in Norway and Svalbard. NINA Report 1151. NINA, Trondheim, p 84Google Scholar
- Grémillet D, Lewis S, Drapeau L, van Der Lingen CD, Huggett JA, Coetzee JC, Verheye HM, Daunt F, Wanless S, Ryan PG (2008) Spatial match-mismatch in the Benguela upwelling zone: should we expect chlorophyll and sea-surface temperature to predict marine predator distributions? J App Ecol 45:610–621. doi: 10.1111/j.1365-2664.2007.01447.x CrossRefGoogle Scholar
- Halpern BS, Walbridge S, Selkoe KA, Kappel CV, Micheli F, D’Agrosa C, Bruno JF, Casey KS, Ebert C, Fox HE, Fujita R, Heinemann D, Lenihan HS, Madin EMP, Perry MT, Selig ER, Spalding M, Steneck R, Watson R (2008) A global map of human impact on marine ecosystems. Science 319(5865):948–952. doi: 10.1126/science.1149345 CrossRefGoogle Scholar
- Lascelles BG, Taylor PR, Miller MGR, Dias MP, Oppel S, Torres L, Hedd A, Le Corre M, Phillips RA, Shaffer SA, Weimerskirch H, Small C (2016) Applying global criteria to tracking data to define important areas for marine conservation. Divers Distrib 22:422–431. doi: 10.1111/ddi.12411 CrossRefGoogle Scholar
- Luque SP (2007) Diving behaviour analysis in R. R News 7(3):8–14Google Scholar
- Mehl S (2015). Northeast Arctic saithe. In: Havforskningsrapporten 2015. Fisken og havet, særnr. 1–2015, p 184Google Scholar
- Mitchell PI, Newton SF, Ratcliffe N, Dunn TE (2004) Seabird populations of Britain and Ireland. T. & A.D. Poyser, LondonGoogle Scholar
- Orians GH, Pearson NE (1979) On the theory of central place foraging. In: Horn DJ, Mitchell RD, Stairs GR (eds) Analysis of ecological systems. The Ohio State University Press, Columbus, pp 154–177Google Scholar
- Pebesma EJ, Bivand RS (2005) Classes and methods for spatial data in R. R News 5 (2). http://cran.r-project.ord/doc/Rnews/
- Pethon P (1998) Aschehougs store fiskebok. Aschehoug. (In Norwegian), NY. http://www.asdar-book.org/
- R Development Core Team (2016) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Redfern JV, Ferguson MC, Becker EA, Hyrenbach KD, Good C, Barlow J, Kaschner K, Baumgartner MF, Forney KA, Balance LT, Fauchald P, Halpin P, Hamazaki T, Pershing AJ, Qian SS, Read A, Reilly SB, Torres L, Werner F (2006) Techniques for cetacean-habitat modelling. Mar Ecol Prog Ser 310:271–295. doi: 10.3354/meps310271 CrossRefGoogle Scholar
- Sakshaug E, Bjørge A, Gulliksen B, Loeng H, Mehlum F (1994) The ecosystem Barents Sea (In Norwegian). Universitetsforlaget, Oslo. Norwegian title: Økosystem BarentshavetGoogle Scholar
- Skjoldal HR (ed) (2004) The Norwegian Sea ecosystem. Tapir Academic Press, TrondheimGoogle Scholar
- Wanless S, Harris M (1997) Shag. The birds of the Western Palearctic update 1:1–13Google Scholar
- Wanless S, Harris MP, Burger AE, Buckland ST (1997) Use if time-depth recorders for estimating depth and diving performance of European shags. J F Ornithol 68:547–561Google Scholar